High intensity radiation, such as a stationary pulsed laser beam may be focused on a moving target tape (e.g. copper, stainless steel, etc.) in order to generate x-rays. The intersection of the radiation and the tape defines a point source from which the x-rays radiate. In the process, holes or spots are formed on the target tape. Since the spatial position of the x-ray point source must be stationary, the tape must move in a pattern to allow a fresh portion of the tape to be exposed to each succeeding laser pulse.
The conventional approach for a target tape is to move the tape from the feed reel to the collect reel. This approach utilizes only a single straight line along the tape. A more efficient approach would be to step the tape drive assembly vertically (for a horizontally moving tape) every time the tape reaches the end for multiple vertical passes. The drawbacks of this approach are (1) that the tape is often deformed by the laser ablation process which results in some unstable x-ray generation and (2) the tape drive mechanism requires sophisticated motion control.
It is known that in standard video recorders in common use today, the recording head rotates at a slight angle to the tape and the tape advances relatively slowly so that information can be extracted from almost the entire area of the tape.
What is needed is a mechanically simple point source x-ray tape drive that would enable utilization of the entire tape surface as the tape moves from the supply reel to the collect reel.